Three protocols, one internet
TCP and UDP move data between machines. TLS protects it along the way. Here's what each one actually does.
Transmission Control Protocol
A connection-oriented transport protocol that provides reliable, ordered delivery of data between applications, with built-in error detection and retransmission.
Transport Layer Security
A cryptographic protocol that protects data exchanged between systems — encrypting it, verifying it hasn't been tampered with, and authenticating the server's identity.
User Datagram Protocol
A connectionless transport protocol that prioritizes low overhead. It doesn't guarantee delivery or ordering, leaving that to the application when it's needed.
Where each protocol sits
TCP and UDP are transport protocols. TLS is a security layer that runs above them — not a third alternative transport.
Traditionally TLS runs on top of TCP (as with classic HTTPS). Modern protocols like QUIC instead combine TLS 1.3's cryptographic handshake directly with UDP — TLS still handles security, UDP still handles transport.
TCP — Transmission Control Protocol
Transport Layer · Connection-Oriented
TCP is a connection-oriented transport-layer protocol designed to provide reliable, ordered delivery of data between applications. Before any data is exchanged, the two sides establish a connection; once established, TCP tracks every byte sent so it can detect loss and retransmit as needed.
UDP — User Datagram Protocol
Transport Layer · Connectionless
UDP is connectionless and focuses on low overhead rather than guaranteed delivery. There's no handshake and no built-in retransmission — datagrams are simply sent. This makes it well suited to applications where avoiding connection-management overhead matters more than guaranteed delivery, though it isn't automatically faster in every situation; actual performance depends on the application and network conditions.
Each datagram travels independently — no acknowledgment is required at the protocol level.
TLS — Transport Layer Security
Security / Cryptographic Layer
TLS is a cryptographic protocol used to protect data exchanged between communicating systems. It provides three core security properties:
TLS normally runs above a transport protocol such as TCP. Modern protocols such as QUIC instead pair TLS 1.3's cryptographic handshake with UDP.
TCP vs UDP
Neither protocol is universally "better" — each trades reliability for overhead differently.
| Feature | TCP | UDP |
|---|---|---|
| Connection | Connection-oriented | Connectionless |
| Reliability | Yes | No built-in delivery guarantee |
| Ordering | Yes | No built-in ordering guarantee |
| Retransmission | Yes | No |
| Flow control | Yes | No |
| Congestion control | Yes | No built-in TCP-style mechanism |
| Overhead | Higher | Lower |
| Typical use | Web, APIs, file transfer, SSH | DNS, streaming, gaming, real-time media |
Where are these protocols used?
- HTTPS connections traditionally carried over TCP
- SSH
- FTP
- Email protocols
- Database connections
- Reliable application communication
- DNS queries
- VoIP
- Real-time media
- Online multiplayer networking
- DHCP
- Apps where application-managed reliability is useful
- HTTPS
- Secure APIs
- Secure email transport
- Secure application connections
- Certificate-based server authentication
HTTPS commonly means HTTP protected by TLS. Modern HTTP/3 uses QUIC over UDP with TLS 1.3.
See the conceptual flow
The short version
EDUCATIONAL VISUALIZATION ONLY
FIREPROO NETWORK is a self-contained, front-end demonstration of how common network protocols behave conceptually. All handshake logs, packet counters, and terminal output are generated locally in your browser for illustration — nothing here connects to, scans, or transmits data to any real host. It's built for learning protocol fundamentals: OSI layers, ports, connection models, and encryption posture, at a glance.